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Stone Mountain State Park, NC 3.1.2 October 2002
Instructions:
Set the stage by asking stu -
dents to describe local rocks or
rock formations, or ones that
they have seen during walks
along a river’s edge, on a
mountain, or during drives
along highways that were built
through road cuts. Be sure to
have several rock samples dis -
tributed around the room.
Ask the students questions
such as, “ Have you ever won -
dered just how these rocks
form?” and “ Are new rocks
forming at this moment?”
Ask each student to write
down one rock - related ques -
tion they would like to have
answered in class. Have stu -
dents read the Student's Infor -
mation and accompanying
Rock Cycle Diagram. Discuss
the three classifications of
rocks: sedimentary, metamor -
phic and igneous. You may
also want to introduce the geo -
logic history of Stone Moun -
tain given on page 1.7.
Part A: Weathering
Each student should com -
plete “ The Pressure’s On”
worksheet as they do this ac -
tivity. Cover all desk tops with
newspaper. Give each student
a sheet of wax paper, a pocket
pencil sharpener and four cray -
ons of the same color. The
crayons represent rock material
and the pencil sharpeners rep -
resent weathering agents.
Students should remove the
paper from the outside of their
crayons and carefully shave
the crayons with the pencil
sharpener. All of the crayon
fragments ( which represent
rock sediments) should be
kept in a small pile on the wax
paper. Do not mix the colors –
each student should use his/ her
own piece of wax paper.
As the students are “ weath -
ering” their crayons, call their
attention to the size and shape
of the fragments. Remind
them that many of the rocks in
the Blue Ridge Mountains to -
day probably have their ori -
gins in sediments that accumu -
lated in an ancient ocean over
700 million years ago. Dis -
cuss the following questions:
• Do you think that weath -
ered fragments of rocks are all
the same size or shape?
( Answer: No.)
• Why or why not?
( Answer: The process of
weathering depends on the
chemical composition of the
rock as well as environmental
factors such as temperature,
humidity, the presence of
plants and animals, etc.)
• What are some of nature’s
weathering forces?
( Answer: Mechanical weath-ering
forces can include water,
ice, wind, growing roots,
worms and burrowing ani -
mals, lightning and human ac -
tivities. In addition, heating
and cooling can cause rocks to
expand and contract, and then
break.
Chemical weathering
forces include oxygen, carbon
dioxide and water, which react
with a rock or mineral result -
ing in a chemical change. At
Stone Mountain, a chemical
weathering process called ex-foliation
causes curved sheets
of rock to be sloughed off like
the layers of skin on an onion.
When the “ weathering” is
complete, the students should
wrap their fragments in wax
paper and place each wax pa -
per packet in an envelope, un -
less you plan to do Part B im -
mediately. Label each enve -
lope as to its contents, “ red,”
“ yellow,” etc., for proper
distribution when the activity
is resumed.
Part B: Erosion
Once rock fragments have
been created, they are usually
moved by some force of na -
ture. Here, the students act as
the erosive force as they move
the envelopes containing the
fragments within the room.
• What is this force of
movement called and what are
some of its causes? ( Answer:
Erosion, caused by water –
such as streams, rivers and
ocean waves – and by wind.)
• Where do rock fragments
tend to collect? ( Answer:
Downhill from where they
were first formed.)
• Why? ( Answer: Gravity.)
• Why do similarly - sized
fragments seem to be found
together?
( Answer: Because similar
weathering processes will usu -
ally take place in one particular
area. Smaller, lighter rock
fragments will be carried far -
ther away in a winnowing ef -
fect.)

Stone Mountain State Park, NC 3.1.2 October 2002
Instructions:
Set the stage by asking stu -
dents to describe local rocks or
rock formations, or ones that
they have seen during walks
along a river’s edge, on a
mountain, or during drives
along highways that were built
through road cuts. Be sure to
have several rock samples dis -
tributed around the room.
Ask the students questions
such as, “ Have you ever won -
dered just how these rocks
form?” and “ Are new rocks
forming at this moment?”
Ask each student to write
down one rock - related ques -
tion they would like to have
answered in class. Have stu -
dents read the Student's Infor -
mation and accompanying
Rock Cycle Diagram. Discuss
the three classifications of
rocks: sedimentary, metamor -
phic and igneous. You may
also want to introduce the geo -
logic history of Stone Moun -
tain given on page 1.7.
Part A: Weathering
Each student should com -
plete “ The Pressure’s On”
worksheet as they do this ac -
tivity. Cover all desk tops with
newspaper. Give each student
a sheet of wax paper, a pocket
pencil sharpener and four cray -
ons of the same color. The
crayons represent rock material
and the pencil sharpeners rep -
resent weathering agents.
Students should remove the
paper from the outside of their
crayons and carefully shave
the crayons with the pencil
sharpener. All of the crayon
fragments ( which represent
rock sediments) should be
kept in a small pile on the wax
paper. Do not mix the colors –
each student should use his/ her
own piece of wax paper.
As the students are “ weath -
ering” their crayons, call their
attention to the size and shape
of the fragments. Remind
them that many of the rocks in
the Blue Ridge Mountains to -
day probably have their ori -
gins in sediments that accumu -
lated in an ancient ocean over
700 million years ago. Dis -
cuss the following questions:
• Do you think that weath -
ered fragments of rocks are all
the same size or shape?
( Answer: No.)
• Why or why not?
( Answer: The process of
weathering depends on the
chemical composition of the
rock as well as environmental
factors such as temperature,
humidity, the presence of
plants and animals, etc.)
• What are some of nature’s
weathering forces?
( Answer: Mechanical weath-ering
forces can include water,
ice, wind, growing roots,
worms and burrowing ani -
mals, lightning and human ac -
tivities. In addition, heating
and cooling can cause rocks to
expand and contract, and then
break.
Chemical weathering
forces include oxygen, carbon
dioxide and water, which react
with a rock or mineral result -
ing in a chemical change. At
Stone Mountain, a chemical
weathering process called ex-foliation
causes curved sheets
of rock to be sloughed off like
the layers of skin on an onion.
When the “ weathering” is
complete, the students should
wrap their fragments in wax
paper and place each wax pa -
per packet in an envelope, un -
less you plan to do Part B im -
mediately. Label each enve -
lope as to its contents, “ red,”
“ yellow,” etc., for proper
distribution when the activity
is resumed.
Part B: Erosion
Once rock fragments have
been created, they are usually
moved by some force of na -
ture. Here, the students act as
the erosive force as they move
the envelopes containing the
fragments within the room.
• What is this force of
movement called and what are
some of its causes? ( Answer:
Erosion, caused by water –
such as streams, rivers and
ocean waves – and by wind.)
• Where do rock fragments
tend to collect? ( Answer:
Downhill from where they
were first formed.)
• Why? ( Answer: Gravity.)
• Why do similarly - sized
fragments seem to be found
together?
( Answer: Because similar
weathering processes will usu -
ally take place in one particular
area. Smaller, lighter rock
fragments will be carried far -
ther away in a winnowing ef -
fect.)